Until now, the vampire bat has not caused any problems for humans, as he fed mostly on birds. Now, researchers found out that some of them that are located in the Northern Brazil started to become a threat.

At night, the bats feed on human blood. The Federal University of Pernambuco from Brazil is the one that made the shocking discovery.

Enrico Bernard, a scientist, declared that all the team was really surprised as “this species isn’t adapted to feed on the blood of mammals.”

There are three species of bats and only one is known for feeding on human blood, the common vampire bat. Although it can attack humans, it rarely chooses too. Its targets are usually animals, such as cows, pigs or horses.

Now the hairy-legged bat and the white-winged one have also started to feed on humans. They usually feed on birds and the change to human blood would require some transformations. They have to adapt their behavior, morphology and physic.

They have to adapt since the bloods are really different in nutrients. The bird blood has more water and fat content, while the human blood has more proteins.

Another study shows that for some bats, the change of bloods affected them badly and made them starve to death.

The team form the Brazilian university, after research, found out that three of the samples they had contained both bird and human DNA.

Their behavior can be caused by the extinction of many birds in that area and since humans have chickens, they decided to attack both of them. “House conditions in Catimbau are usually poor, and domestic animals are usually in close contact with humans, what may explain the occurrence”, said the team.

There is not known yet whether they represent or not a real threat to humans.